Crystal-field interaction in the GdxEu1−xBa2Cu3O7−δ superconductors

M. T. Causa; C. Fainstein; G. Nieva; R. Sánchez; L. B. Steren; M. Tovar; R. Zysler; D. C. Vier; S. Schultz; S. B. Oseroff; Z. Fisk; J. L. Smith

doi:10.1103/PhysRevB.38.257

Crystal-field interaction in the GdxEu1−xBa2Cu3O7−δ superconductors

M. T. Causa, C. Fainstein, G. Nieva, R. Sánchez, L. B. Steren, M. Tovar, R. Zysler, D. C. Vier, S. Schultz, S. B. Oseroff, Z. Fisk, J. L. Smith

DOI 10.1103/PhysRevB.38.257 · Physical Review B

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Abstract

We report here experimental data on the crystal-field interaction of gadolinium ions with their environment in GdxEu1−xBa2Cu3O7−δ. The ESR spectrum and a Schottky anomaly in the specific heat of dilute samples (x≪1) indicate the existence of a crystal-field splitting of the S728 ground state of Gd3+ ions of about 1.5 K. We discuss the parametrization of the measured splitting in terms of an effective Hamiltonian, and the microscopic origin of the interaction within the framework of a superposition model. Since the single-ion energies involved are of the same order of magnitude as the energies associated with the magnetic ordering of the Gd3+ moments in GdBa2Cu3O7−δ (TN≅2.24 K), we analyze the effects of the crystal-field interaction on the magnetic transition.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
GdxEu1-xBa2Cu3O7-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	90	Pressure not reported	onset
YBa2Cu3O7-δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	90	Pressure not reported	onset